Christ's College, alma mater of John Milton, Charles Darwin and Channel 4's Richard Whiteley, is a double winner in this year's Tompkins table of Cambridge University examination results.

Christ's College, alma mater of John Milton, Charles Darwin and Channel 4's Richard Whiteley, is a double winner in this year's Tompkins table of Cambridge University examination results.

Christ's is not only top of this year's table but is also the best performer over time in the table compiled for The Independent by Peter Tompkins, who is a partner in PricewaterhouseCoopers.

Mr Tompkins, who first produced the table when he was in his final year reading maths at Trinity College, Cambridge, has celebrated its twentieth year by giving colleges' performance during that time.

When he first drew it up "out of curiosity", his tutor told him dismissively: "No one is going to take any notice of this." Now colleges inquire anxiously about their placing.

Mr Tompkins says the 20-year table provides a better guide for dons and prospective students than the annual one. Clare College, which is ninth in this year's table, comes second. Neither Christ's nor Clare has been in the bottom third of the table. Nor have Trinity and Caius, though the latter has yet to make the top slot.

Though some colleges such as St John's have been very high or very low, on the whole the position of the top and bottom colleges is reasonably consistent. Newnham is at the foot of this year's table, for the second year running, just above Sidney Sussex, which fell to its lowest place since the table began. King's, which was top for five years in a row at the start of the 1990s, also fell to its lowest position. Trinity just beats Christ's for the highest proportion of firsts - 32.5.

Kevin Bowkett, senior tutor at Christ's, said: "We have done well for so long that schools tend to send us pupils who have done particularly well. Our students do well because they work very hard but they also play very hard." The college uses A-levels and interviews to pick its students: it believes written tests set by some colleges disadvantage state school pupils. "We allow for pupils' backgrounds through the interview system," he said. The college takes about the same proportion of state pupils as the university as a whole - just over half.

Penny Wilson, the secretary of the university's senior tutors' committee, said: "The tables do have some value as a monitor of how colleges are doing year by year. My worry is that they might distract us from the more important issue of access. There is a risk that colleges might be unwilling to take a risk with someone who shows potential rather than someone who has been well coached."

Mr Tompkins said: "I don't take it as seriously as some other people do. It is a general pointer to good quality and low quality. If some people who are lower in the table put a bit more effort into their admissions, it might have a good effect."

Results are shown as a percentage of the maximum possible points if every student had a first, with five points for a first, three for an upper second, two for a lower second and one for a third.

Oxbridge college tables are controversial. Eight years ago Oxford dons tried to stop the Norrington table, their equivalent of the Tompkins table, by removing college names from degree lists. They said the tables gave a misleading impression of performance. But students compiled unofficial tables and Oxford reinstated the college names in 1998.